Bug Description

Binary package hint: devicekit-power

A lot of laptop have no backlight (brightness support) because of missing kernel support, and waiting for fix in hal...
In fact, the utility smartdimmer, in main repository, is providing everything need : a get and set method for backlight...

As hal will be depreciated, it would be nice, if it could be fixed in devicekit... and people having vaios, samsung and so could after a couple of years have full power management !

Schmirrwurst [2009-07-22 17:30 -0000]:
> If this has to be fixed in gnome-power-manager, which package is
> repsponsible for kde ?? I've seen that the kde power management is
> still relying on hal-power under karmic....

Well, it really needs to be fixed in X.org (the XBACKLIGHT extension),
in hal, DevKit, or anywhere else there is simply no way to get it
right (if you consider multi-monitor setups, xrandr configurations,
etc., and also the fact that X.org _also_ controls the backlight in
some way).

Is it the case that Ubuntu 9.10 might not support brightness hot keys
on my laptop? If so, this is a serious regression from Jaunty.

On Wed, Jul 22, 2009 at 1:10 PM, Martin Pitt<email address hidden> wrote:
> Schmirrwurst [2009-07-22 17:30 -0000]:
>> If this has to be fixed in gnome-power-manager, which package is
>> repsponsible for kde ?? I've seen that the kde power management is
>> still relying on hal-power under karmic....
>
> Well, it really needs to be fixed in X.org (the XBACKLIGHT extension),
> in hal, DevKit, or anywhere else there is simply no way to get it
> right (if you consider multi-monitor setups, xrandr configurations,
> etc., and also the fact that X.org _also_ controls the backlight in
> some way).
>
> Please see
> http://lists.freedesktop.org/archives/devkit-devel/2009-July/000268.html
>
> for some details.
>
> --
> no backlight support for laptop (hal depreciation regression)
> https://bugs.launchpad.net/bugs/385723
> You received this bug notification because you are a direct subscriber
> of the bug.
>

I've red the thread you mentioned, and I found out in it, that it should be fixed in xbacklight, but this could take quite a long time... and there is need of a fallback solution !

How many years do people experiencing that problem (on hp, samsung, sony, mac laptop...) are going to wait to have their laptop properly working ? Even Microsoft is shipping a new software, are tell the user they have to wait 2 years until another project close the gap...

I can understand that it is the right way, but how can we get a fallback solution for karmic ???

The hal support for smartdimmer isn't going away anytime soon, so for these platforms it's perhaps possible to add back the gnome-power-manager support for it. That's why there is a gnome-power-manager task here.

But I see no chance of devkit-power ever getting support for smartdimmer. The entire idea of smartdimmer is a hack, device drivers belong into kernel just as any other backlight interface the kernel offers. If X.org merges the smartdimmer logic in its xbacklight support, that's fine of course.

I've a sony vaio with geforce 8400M GT, and I've no support for backlight, no laptop_panel in hal, no entry in /sys/class/backlight

I've reported the bug in hal, in devicekit, in kernel, by nvidia...

In fact, a lot of people are affected with this problem on laptops from hp, samsung, sony and mac.

-Hal is deprieciated
-devicekit won't fix some device specific issue
-nvidia is not supporting backlight, as every manufaturer is managing it differently
-kernel team is not reacting

I'm waiting already 2 years for a solution ! I hope to have it fixed for karmic, if not, we all are to wait 6 other month !

Martin Pitt (hal/devicekit developper) said he could make it work if xorg could fix it in xbacklight...
There is already the utility smartdimmer (or nvclock) that is able to set or get backlight, it could be possible to use that code...

The entire idea of smartdimmer is a hack, device drivers belong into kernel just as any other backlight interface the kernel offers. If X.org merges the smartdimmer logic in its xbacklight support, that's fine of course.

The hal support for smartdimmer isn't going away anytime soon, so for these platforms it's perhaps possible to add back the gnome-power-manager support for it. (We could use this bug for tracking that.)

Do xbacklight needs to have the nvidia driver in use to work ? is it communicating through the driver ?

I know from nvidia that they won't support backlight in the driver because the manufacturer are managing backlight differently...
(if it is another issue, do it has been reported somewhere by nvidia ?)

smartdimmer and nvclock are working even without having the driver installed. Could it be possible to change xbacklight the same way for the nvidia cards that are making problems ?

You said "hal support for smartdimmer isn't going away anytime soon", but for me hal never manage to get my backlight to work, In one bug report in LP, I know a change has been made for nvidia user, to use smartdimmer, but this is not working for user that do not have laptop_panel in lshal.. like me
That's why I opened that bug report :https://bugs.launchpad.net/hal/+bug/345531

If hal would be fixed, it would mean that everything could be fine under gnome and kde ?

How fast could it be to make hal work without laptop_panel ?

I've already opened a bug for xbacklight... (and still nothing from kernel team)

However, there's a kernel driver available since early 2009 in the Mactel repository (https://launchpad.net/~mactel-support/+archive/ppa/+packages), that isn't specific to Apple machines and is known to work on my machines (might not auto-load). Also works on Lucid and can be used with pommed as well.

(1) The original bug report mentions smartdimmer, Nvidia, and Geforce. Thus, the bug seems to be related to Nvidia graphics. The driver nvidia_bl in the mactel repository, which isn't specific to Apple machines, it is just there, might help. As well as the mentioned X.org option (EnableBrightnessControl) which is to be used with the Nvidia proprietary graphics driver.

(2) Your machine (MacBook4,1) incorporates an Intel graphics adapter. So the suggestions obviously won't help. (And pommed isn't necessary, but useful anyway.) For your machine, you might try mbp_nvidia_bl instead. This one is Apple-specific, but despite its name not restricted to MacBook Pros. Afaik, the upstream version (and thus, karmic and lucid) doesn't support your machine yet, but my patches have been accepted recently, so it might work when lucid gets released. In the meantime you might try the patched version in present the mactel PPA.

For me on sony fz, EnableBrightnessControl isn't working with the glx drivers...
The nvidia_bl isn't working for me (I tried karmic version, there is no lucid one), and in the description, it is supposed to support only NV40 and <, not NV50 like my geforce 8...

The report is about missing backlight support in ubuntu for nvidia glx. Nvidia won't do anything, hal either, so that ubuntu users are missing backlight control since 5 years, and there is no real solution for the moment...

Smartdimmer is now able to set and get backlight information for those cards, but is not yet used by ubuntu for backlight management. a nvidia_bl module is probably the right way, because devicekit is rejecting the idea to write a specific code to use smartdimmer for nvidia hw... But I think if on the side from ubuntu nothing is to be done, than ubuntu users will have to live without backlight support for again 5 years or more... and quite a lot of notebooks are shiped with nv hw.... not only mac but also sony, samsung, dell, acer...

On fresh Lucid. Just install the package, add line "nvidia-bl max_level=1026" to /etc/modules and reboot. Does not work properly without parameter on my laptop. Parameters values that work are from 1024 to 1029 or so...

Just one thing more, I can not set full backlight with hotkeys (Fn+F5/F6), always one step lower. If I press BrightnessUp key many many times Smartdimmer still shows 95, the maximum is 100, "cat /sys/class/backlight/bla-bla-bla" is one step lower the maximum too. All other backlight functions work just fine.

The problem on VAIOs is that there is no laptop_panel device in hal with proprietary nvidia driver. There are some scripts to manage backlight through Smartdimmer on VAIOs and Smartdimmer works fine in latest Ubuntu distros. But these scripts do not work because hal does not recognize laptop_panel device.

Backlight management works fine with nouveau driver but this driver has no 3D acceleration yet.